Candidate vaccines for prevention or therapy of HCV infection should be evaluated first in mice and a small nonhuman primate such as the rhesus macaque. In macaques, one significant obstacle is MHC heterogeneity. Identification of epitopes presented by the most prevalent class I molecules would greatly facilitate vaccine development. The Mamu A*01 molecule is present in 30% of macaques originating from India. Accordingly, our first goal will identify HCV-derived Mamu A*01 restricted epitopes. Furthermore, we propose to utilize adeno-associated virus (AAV) vectors, originally designed for delivery to the liver of therapeutic genes, to investigate the effects of expression of HCV antigens in hepatocytes of immune-competent animals. We will construct recombinant vectors that express HCV structural and non-structural proteins, and assess RNA persistence and antigen expression in the liver of mice injected with AAV vectors. Cellular immune responses and liver pathology will also be monitored. Phase II studies will further develop the murine and macaque models. In both systems we will test the effect of immunization with class I and class II epitopes expressed by DNA plasmids, appropriate viral vectors and/or autologous dendritic cells. The ability of these vaccines to elicit T cells and ultimately clear antigen-positive hepatocytes will be determined. PROPOSED COMMERCIAL APPLICATIONS: The overall focus of our research is to develop a vaccine for prevention and treatment of HCV infection. The proposed research will develop an adequate system for testing the multi epitope approach to immunotherapy in non-human primates and HLA transgenic mice.